If you're newer to the game and you see a cool adventure that uses a different version of the D&D rules, you might back off, thinking that converting it is too much work.

It's not! It's worth it! There are a lot of cool old adventures that virtually nobody has played. Converting can take a while, but it doesn’t have to. If you’re a stickler and you want to get every little detail right, it will take forever. But that’s not necessary at all. You can slap stuff together and run it just fine.

Guidelines: There are two very important pages in the DMG:

DC guidelines on page 238.

Damage guidelines on page 249.

Online Tools: Nobody can remember every spell and item in existence. When you need to know 5e stuff, you can ctrl-f and search these lists real quick:

Tons of Treasure: In older editions, magic items are handed out by the truckload in published adventures. In 4e, magic items are expected. You have to have them!

In 5e, magic items are rarer. Adventuring groups have less of them and, at least in my games, a +2 item is ridiculously rare. I don't think I've ever given one out! In older editions, +2,+3, no big deal. +5 is usually the big time in the olden days.

I'm going to go through each edition, list some adventures and show how to convert stuff from that edition.

AD&D 1st Edition – Temple of Elemental Evil

Certain 1st edition adventures such as Tomb of Horrors and White Plume Mountain are reprinted in almost every edition, just like in 5e's Tales From the Yawning Portal.

Low AC: A low armor class is good in 1st edition. Once you get in the negatives, it's very good. AC -2 is fantastic. That’s +4 plate mail you’re wearing, there.

No Balance: The big thing to know as a DM is that most of the time, there's no encounter balance in 1e and 2e adventures! There is no math, they just threw whatever they felt like at you.

So when you're converting 1e adventures, keep that in mind. If there's a room with 20 orcs and your group is 3rd level, you have a choice: Leave it as-is or balance it. I think that kind of depends on your style and the temperament of your players.

Maintaining the Balance: If you want to balance it, go to kobold fight club and enter in your stuff. A medium challenge for four 3rd level characters would be three orcs. So you just change that room to 3 orcs instead of 20.

I converted and ran the Temple of Elemental Evil a few years ago. You might want to check out the computer game. It is buggy, but you will probably end up really excited about running this adventure. I did, anyway.

Modify It: Do not feel weird about changing things or removing sections of the dungeon that seem boring to you. Every DM does it in every edition. In the case of this adventure, this dungeon is very uneven and some of it might be a drag to play through.

Chamber of Statues (page 78, Room 311)

I picked this room because I like it a lot, and it has a lot of examples of the choices you will have to make when converting. The above image doesn't include the whole room. There's all these statues in here, too.

Scaling the Wisps: The lights are four will-o'-wisps. The 5e version of them is on MM page 301. The wisps attack the group as they look at the statues. If the group consists of four heroes that are 5th level, then 4 will-o'-wisps is a hard encounter. You could drop it to 3 wisps to make it a medium encounter.

If two wisps are slain, the others flee, which makes the encounter a bit easier. But it's a tricky choice. I'd go with less wisps, because the fun of this room has nothing to do with them. This room is all about experimenting with the statues.

Beholder Statue: It is protected by a fire trap and it has a scroll of protection from magic.

So.. I don’t see a 5e fire trap. Let's google fire trap from an older edition. It's right here.

Basically, you touch the fire-trapped thing and there's a fiery explosion. For damage and DCs, you can use the guidelines on DMG pages 238 and 249. I usually stick with DCs that are between 10-15, because even high-level characters have a hard time making those rolls.

I'd go with a DC 13 Dexterity save and 2d10 fire damage. Success = half damage. If the group is 5th level here, we're right on the border of 'setback' and 'dangerous' on page 249. I might split the difference and go with 3d10 fire damage.

I think I would have it hit everyone within 5 feet of the object. That’s always tricky because you need to know who is close without tipping the players off that it matters where they’re standing.

Dragon Statue: The box that the dragon statue is admiring has invisible runes on it. They reveal four command words:

Shrinks the box to 1/12th normal size.

Causes it to function as a Leomund's secret chest spell.

Causes the box to go back to full size.

Makes the box four times as large! It weighs 1,200 pounds.

Invisible Runes: Invisible runes! How do we decide if they're detected? Who scans every item for invisible text on it?

I would do it like a 5e glyph of warding, where the words are nearly invisible and require a successful Intelligence (Investigation) check to find. So, if the group is smart and cautious, they'll check it for traps.

No DC: In cases like these, I just let the group find it if they say they are looking. I don't like it when the group has the foresight to search something and then don't find anything because of a die roll. If they were clever enough to check, I'd give it to them.

Leomund's secret chest is on PH page 254.

Weaponized Box: One pitfall here. Your players will definitely try to drop the box from a height onto a bad guy and speak the command word so that the 1,200 pound box comes crashing down on them.

That's fun and hilarious once, but it could march into cheesy territory real easily. You might want to say that it takes the box d6 rounds to fully expand and that it makes a stretching, creaking noise when it does so.

Or! The group drops it and expands it. It falls, hits the target and cracks. It doesn’t break, but it is clear if they do it again, the box will fall apart and be useless.

Fire Giant: Has a +2 spear, cursed backbiter.

This item is in Tales from the Yawning Portal, page 229. Let’s assume you don’t have that book. We google it.

Magic Curse: The deal here is that when you roll a natural 1, it damages the wielder. Usually with these kind of items, the wielder will be affected by it magically and won't want to get rid of it. Remove curse will need to be cast to separate the wielder from the item.

In this case, I think it would be funny to say that it is just a faulty spear. The character gets hit with it one time, and they can either throw it in the garbage or maybe use it in a clever way, convincing an enemy to wield it so that they end up killing themselves with it, which would be really funny.

Manticore: It has a crossbow of speed, but the crossbow's string is missing. It says that "enchant weapon" is needed to fix it. Furthermore, the bow's new string will break whenever the wielder rolls a natural 20 to hit.

There's no crossbow of speed in 5e, but there is a scimitar of speed (DMG page 199). It's +2 and it lets you make one more attack with it as a bonus action on each of your turns. That's easy to apply to this, right?

Fixing the String: Enchant weapon isn't in 5e. It seems like the cantrip "mending" (PH page 259) would fix this just fine.

Medusa: Oh boy. Cloak of poisonousness. When you put it on.. you die. No saving throw.

That's brutal! I don't like stuff like this. If you are going to use this item, I think you should warn your players when you start this adventure that there is save or die effects in it. They'll be more cautious and they deserve a heads up. Also, it might save you some headaches if/when they die from it.

If I was going to use this item, I would make the DC low. DC 10. I'd probably also describe it in an ominous tone, and say that it slithers anxiously like a snake, eager for you to wear it.

Changing It: I think I would change this completely. I'd probably alter it to an effect where the hero is cursed and very slowly turning to stone. Each day, they lose a bit of speed and maybe gain 1 point of AC. They'll be petrified within a week, giving them ample time to remove it if they want.

I'd also love the idea of the character becoming more medusa-like. They start to grow snake hair, and their gaze sometimes turns things to stone, but they can't control it. Eventually they'd start to lose control and they'd need a remove curse before they became an NPC monster.

Players love this kind of thing, and frequently they'll request to keep the effect in some way. They might just like the snake hair. I usually let them keep it, because it's fun. I did a thing in a Blackmoor campaign where some of the heroes turned into slaads in times of stress as if they were the Hulk. They loved it so much, I just let them keep it.

Don’t Worry About It: As long as it doesn't unbalance the game, stuff like this can help get the players more into their character. That character is now utterly unique, and they are rewarded for interacting with the world.

Mummy: The staff has a glyph of warding (blindness) on it. The bottle contains strong acid that can be thrown like a grenade.

Glyph of Warding is on PH page 245, blindness/deafness is on PH page 219. That's a Con save. The blindness spell only lasts a minute, which feels a bit useless. Then again, being blind in a dungeon for a long time sucks.

Timing: I think what I'd do is have the wisps play it cool and wait for someone to be blinded, and then attack. That way the blindness matters without it being too harsh.

Lords of Acid: The acid grenade. I googled a 5e vial of acid. It does 2d6 acid. Since this bottle has "strong acid" let's double the damage! 4d6 acid right in the face!

Ogre Mage: The necklace has a stone that can be thrown to create an Otiluke's freezing sphere.

Otiluke's freezing sphere is on PH page 263. 60 foot radius, 10d6 damage! That's a cool one-shot item for the group to use in times of peril.

Rakshasa: A ring of delusion which performs as a ring of x-ray vision for one turn before becoming false and useless. Ring of x-ray vision is on DMG page 193.

There is no 5e version of a ring of delusion that I know of. I googled it. The user believes the item is what it appears to be and can't be convinced otherwise without a remove curse.

Cursed Items are Weird: I don't like cursed items because it's too much of a middle finger to the group. Also, how exactly did the bad guy get these things without getting cursed? The bad guy collects them? Does the bad guy expect that many intruders??

Altering It: You can have fun with this, though. You could say that the x-ray vision works half the time, and the other half it shows something really weird. So then, if there is a room where there is actually something bizarre going on, the group will have no idea if the ring is messing with them or not.

Also, you could do it in a way where the ring likes the character and deceives them to keep them safe. That might lead to all sorts of fun things.

Wight: The urn is worth 20,000 gold!!! Inside it is dust of sneezing and choking, which "spills out of the vessel if examined." Each creature within 20 feet is disabled for 5-20 rounds and must save vs. poison... or DIE.

According to that, each hero should have around 560 gold each at 5th level. At 6th, they should have 4500 gold.

Dispensing Cash: Handing out gold partly depends on how you run things. If the group can buy magic items in your world, then the amount of gold they have matters a lot. If they are able to pay spellcasters to cast high level spells for them, that matters too.

Don't Sell Your Timeshare: In D&D, characters don't do a lot with gold. What is there to buy? If you look at the prices of buildings, they are incredibly expensive. A fortress is 150,000 gold. If your group is the type to want to buy a place like that, then handing them this gold is fine! They're saving it for their fortress.

Dust of Death: Dust of sneezing and choking is on DMG page 166. DC 15 Con save or become unable to breathe and begin suffocating. They can repeat the save at the end of each turn.

I would use the dust as it is written in the 5e DMG and remove the YOU DIE part from the 1e adventure. The characters might suffocate to death using the 5e rules, but it will be through the suffocation/exhaustion rules. I hate looking those rules up. I googled it, it's right here.

Heimlich: The choking character can last at least a round before it hits 0 and starts making death saves. The only thing I'd plan for is another character trying to help their friend breathe. Medicine check? You could do an amusing heimlich maneuver or mouth-to-mouth scenario, depending on your group’s sense of humor.

AD&D 2nd Edition - The Rod of Seven Parts

Ok.. this adventure is awesome, but it's very high level. My favorite part of this whole boxed set is the third booklet that details the rod and has scenarios that might occur in the campaign, such as: "What if the group is caught by the bad guys?" That whole possibility is written out like an adventure. I love it.

In this campaign, the Queen of Chaos sends her flunkies after the heroes. She wants the pieces of the Rod of Seven Parts. The group is collecting them while avoiding her deadly spyder-fiends. Let’s convert the weakest type of spyder-fiend from 2e to 5e. Here's the 2e stat block:

We’ll go down the terms so you have an idea of what matters. Most of it doesn’t:

AC: Armor class.

MV: Their speed, which is weird in old editions (they use real-life inches on a real-life map).

Wb 15: I think this is the speed it has climbing webs.

Cl 9: I think this is the spider's climb speed (Thanks Nono).

HD 4: That's the challenge rating of the monster. "Hit dice" in older editions basically meant the "level" of the monster.

# AT 1: Number of attacks per round. It has one attack.

Dmg: Damage.

SA: Spell-like abilities.

SD: Special defenses.

SW: Vulnerabilities.

MR: Magic Resistance. A lot of monsters in 2e have some amount of magic resistance. When a spell is cast at them, they roll a d100. If they get that number or lower, they resist the spell. If the spell bypasses the resistance, the monster still gets to make a saving throw as normal.

SZ: Size.

ML: This is morale, a tool for the DM to figure out if a monster runs away. During a battle when things go bad, you'd make a roll. The lower the morale score, the more cowardly the monster.

THAC0: This is the stuff of legend, the core of the 2e experience. This is 2nd edition's weird way of helping you figure out what you need to roll to hit an armor class. Remember, a low armor class is good in 2e. THAC0 stands for "To Hit AC 0." The lower your THAC0 score, the better.

If you have a THAC0 of 5, that means you only have to roll a 5 on a d20 to hit a monster with an AC of 0. That’s really good!

So a THAC0 of 17 means you need to roll a 17 on a d20 to hit AC 0. Remember, a -1 AC is harder to hit. If you have a THAC0 of 17, you need to roll an 18 to hit a -1 AC.

If you want to hit a regular dude who has an AC of 10, you only need to roll a 7. It's weird, but once you get it in your head, you never lose it, ever.

Spyder Time: OK. To get these spider-y powers right, we should look at the 5e spiders to see how 5e rules use spiders. If you look, a phase spider (MM page 334) seems to be very close to what we want. It is one level lower than I'd like.

Honestly, I would probably just use these stats and add a few hit points and the bite power. But let’s try and do this thing. Basically, I’m taking the spider abilities and scaling them for a challenge 4 monster.

One thing I noticed is that giant spider poison does a pile of damage. I decided to use that. I also chose to limit the teleport power. Teleport at will seems a bit much for a low-level monster. I was torn on giving it the phase spider ethereal jaunt ability. I decided not to just to be faithful to the 2e version.

Kakkuu (Demon, Spyder-Fiend): AC 14 HP 65 Bite: +5 to hit, 6 piercing dmg piercing and the target must make a DC 11 Con save, taking 18 poison on a failed save, or half as much on a successful one. If the target drops to 0, it is stable but poisoned for one hour, even after regaining hit points, and is paralyzed while poisoned in this way.

Immune: Lightning, poison. Resistant: Cold, fire

Web (recharge 5-6): +5 to hit, range 30/60, the target is restrained by the webbing. DC 12 Strength to escape.

Spell-like Abilities: (At-will): Darkness, (3/Day) Teleport.

There's a description of how a kakkuu can dangle a web down and swing it so that the heroes get stuck to it. Then it can reel them in at 15 feet per round. I'd make that an encounter or two, not sure how to word it exactly.

One other thing. You should probably change the name of this monster. If you have a goofy group, once they start saying “Kakkuu” out loud, you’re in for many nights full of ribald humor.

D&D 3rd Edition Life's Bazaar (Dungeon Magazine #97)

Let's do a Perkins! Chris Perkins used this adventure to kick off the first big 3e adventure path - The Shackled City. This path is really awesome, but it is a bit disjointed. The adventures don't connect that well and they don't foreshadow the big final villains, so it comes off a little weird.

This adventure has an awesome level 1 dungeon (called Jzadirune) in it. I actually converted this to 4th edition years ago, and I screwed it up. So, it seems like a good choice to talk about here.

This dungeon has gear doors:

The doors in Jzadirune are gear-shaped.

They roll into a nearby wall cavity when properly opened.

Burned into the center of each door is a glyph representing a letter in the gnome language.

The doors are locked. Opening one requires a rectangular, rod-shaped key.

The key fits in a tiny, diamond-shaped slot, and each key bears a tiny glyph at one end.

The DC on this lock is a 30! At first level! Even in 3rd edition, that's really high.

Problem: What happened in my game was that I made the DC high - attainable, but really high. The thief kept failing his attempts to pick the lock. From the text: "The trap continues to function until the door is opened or destroyed."

The thief kept failing and getting hit with the trap effect over and over. It got unpleasant, to say the least.

Converting the Traps: Each of these doors has a different trap, many of which mirrors the effect of a cantrip. There's a shocking grasp, ray of frost, cloud of corrosive gas, fan of magical flames, etc. I'd use the actual 5e cantrips with a DC of 10 where applicable.

For the other traps, I'd use a DC 10 and damage of 1d10 or maybe even 1d6.

Deciding the DC of the Locks: This dungeon is designed in a way where I think you can get through it without opening one gear door. There's secret doors you can use to traverse the dungeon, and some of the gear doors are open. If I could do this again, I’d have lowered the DC by a lot. I think that DC 30 was some 3e thing that went over my head when converting.

1st Level Characters: This adventure is the beginning of a campaign, so if you have new players, you want to really lowball them on damage while they learn the game.

D&D 4th Edition - Siege of Bordrin's Watch (Dungeon #157)

I didn't like that Tales from the Yawning Portal didn't have a 4e adventure in it. I wracked my brain to think of one to replace Forge of Fury (we don't need two 3e adventures from the same path in Yawning Portal, right?). I realized that it should be Siege of Bordrin's Watch. I ran that and my group talked about it for years after.

Converting 4th Edition: 4e is different. Very different! It's like D&D tactics. I loved it, but I understand why people wouldn't like it.

4e was all about game balance. In older editions, once characters hit 11th level or so, they were so powerful that they could plow through any adventure. Parties would have some characters who were weak and useless, and others who were godlike.

Players would exploit certain combinations which was fun for them, but not so much fun for the players sitting there twiddling their thumbs while their friend killed everything in one round.

4th edition completely removed that. It is extremely balanced, to the point that every class feels similar. Everyone has "powers" that are roughly equal in strength.

4e Monsters: In 4e, the monsters are streamlined. Each has a few powers that are completely explained right there in their stat block. You don't have to look up any spells. They don't have spells! They'll have a power that is like a spell, but it's described right there in the text.

4e Level Range: This adventure is for 3rd level characters. 4th edition goes from levels 1-30, so normally I'd remove a level or two for 5e. You might want to cut them by a 3rd.

For example, if you have a level 12 4th edition adventure, that would be a level 8 5th edition adventure. It doesn't matter that much, it's just something to keep in mind.

In this case, level 3 is fine.

Shrine to Moradin (page 43)

This room has 8 orcs and a cave troll. Most of the orcs are minions, a 4e type of monster that has one single hit point. I love minions, they're a lot of fun and players like slaughtering them.

Remove Orcs: For the conversion to 5e, I'd get rid of all the orcs. The troll is more than enough! After all, a troll is a deadly encounter for four level 3 characters. A troll is a hard encounter for four level 4 characters.

I like this encounter because the monster has a cool power. It's very memorable. "Improvised Weapon" lets the troll grab a creature and use them as a weapon. If the creature has heavy armor on, it does more damage!

We have some options here. We can re-skin the troll so that it's lower level, or we can use the technique from Yawning Portal/Dead in Thay. It's called "reduced threat monsters."

Reduced Threat Monsters: A reduced threat monster has half its normal hit points and -2 to attack rolls, ability checks, DCs and saving throws. That seems simple to put into effect and should shave down our troll from deadly to hard or medium.

We have to create the grabbing-and-hitting power for 5e. Regular trolls are on MM page 291.

Cave TrollAC 13 HP 42 +5/+5/+5 5dmg/5dmg/9dmg

Regeneration: Regains 10 HP at start of its turn unless it takes fire or acid.

(Action) Improvised Weapon: +5 to hit. Hit: Target is grabbed and restrained. The troll uses it as a weapon in a melee attack: +5 to hit, Hit: Both the target and the grabbed creature take 7 damage. If the grabbed creature is wearing heavy armor, the target takes 11 damage. Escaping the grab is an action: Athletics or Acrobatics check DC 11.

There we go. Good enough for a one-off encounter! I'm a little worried about the three attacks. That's a lot of damage. If I were to run this, I'd just spam the improvised weapon power.

You are now a Convert

It might seem daunting, but it doesn’t have to be a big thing. Just slap some appropriate numbers on it and run it! Err on the side of caution and you’ll be fine.

Once you know the appropriate numbers that work for your group, it’s a piece of cake. Any creature you’re unsure of, you can model them after existing 5e monsters of the level you need.